any body know how to rigg bird wing or link of tutorials ? i find it difficult to control the feathers when its fold, thx for help
It depends on how much control you want. Full control means bone structure as shown here:
Main chain of bone goes from Humerus, Ulna / Radius, then to wing tip main bone. From each wing bone segment you need feather bones.
Feather bones points backwards for Humerus and Ulna / Radius segments, when bird wing is extended for flight. But each feather bones must rotate from main wing bone when bird fold its wing. You may be able to just use copy rotation constraint to operate the whole feather rig.
The feather bones in the Primary segment need to be able to “fold up” like a fan.